The assembly of, for example, an automobile involves the application of numerous viscous suspensions such as adhesives, sealants and sound-deadening materials. These suspensions are typically pumped under pressure from a large supply through flexible lines extending from the supply to a point of application and are applied through guns having operator controlled valves to permit controlled applications.
Many suspensions, consisting of both solid particulates and fluid components such as solvents and plasticizers, are known to separate under pressure. If such a phenomenon occurs within the dispensing system, the solid component or components may cake and plug the pump or the lines to the dispensing gun. In a fast moving assembly operation, typical of automotive mass production, the separation of the suspension in the dispensing apparatus may either result in the delivery and application of an improperly balanced mixture or, at worst, may require the dispensing system to be dismantled and cleared by flushing. Production, therefore, is either slowed down or stopped while corrections are made.